Because of their circuit parameter symmetry and negative feedback function, differential amplifier circuits are capable of effectively stabilizing a quiescent operating point, amplifying a differential-mode signal, and suppressing a common-mode signal, and thus they have been widely used at the input stages of directly coupled circuits and measurement circuits.
In differential amplifier circuits, a differential amplifier typically needs a common-mode feedback (CMFB) loop, wherein the CMFB circuit is configured to set a common-mode voltage. At present, many electronic products require low power consumption, and therefore differential amplifiers for use in the electronic products must also strive for reduced power consumption.